Detector



June 23, 1936. `R VELDHUYZEN 2,044,925

DETECTOR Filed Aug. 19, 1951 INVENTOR ROMYN VELDHUYZEN ATTORNEY Patented June 23, 1936 UNITED STATES PATENT OFFICE DETECTOR poration of Delaware Application August 19, 1931,

Serial No. 557,991

In the Netherlands January 16, 1931 3 Claims.

The invention relates to radio receiving circuit arrangements, and more particularly to the circuit arrangement of the detector.

In order to obtain is desirable to utilize two tuned circuits of which cuits on one shaft, and to adjust them simultaneously.

The present invention provides an installation with which the damping is independent of the tuning of the circuits. According to the invention a screen is used as the detector,

The invention by referring to which will be more clearly understood the accompanying drawing, in

(Cl. Z50-27) the anode current as a function of the anode Y voltage at a determined screen grid voltage. 5

In Fig. 1, I is a screen grid tube comprising a cathode 2, a control grid 3, a sceen grid 4, and an anode 5. A tuned input circuit 6, 7 is connected between the control grid and the cathode The screen grid is connected through the primary winding of a transformer 8 to the positive terminal of a battery, the negative side of which is connected to the cathode, an intermediate point I9 of this battery being connected to the anode through a tuned circuit I I, I2. With the aid of the variable connection I0 the tube is adjusted on the verge of self-oscillation, i. e., on the point A, or B, of the characteristic curve shown in Fig. 2. The tube consequently acts as an anode detector.

The damping is exclusively regulated by displacing the point of connection I0. Variation of the anode has no iniiuence on the tuning of any of the circuits 6, 'I or II, I2. For this reason it is pos- 25 sible to mount the condensers 6 and I I utilized in these circuits on a single shaft, shown by dotted line 6.

While I have indicated and described one arrangement for What I claim is: 1. The combination in a receiving circuit of an electron discharge tube having a cathode, a

the screen grid and anode, the screen grid potential being of a higher value than that of the anode, an input circuit tunable to the signal frequency connected between the control grid and cathode, a second circuit tunable to the same frequency as the input circuit connected between the anode and cathode, means for simultaneous- 1y controlling both said tunable circuits, and output coupling means connected to the screen grid.

3. In a radio receiver, a detector stage employing anode circuit rectification comprising a tube including a cathode, control grid, an auxillary grid and a plate anode positioned in the order named, a tuned circuit including a variable condenser tuning element connected between the control grid and cathode, a tuned circuit lncluding a similar variable tuning element con-- nected between the anode and cathode, a source of positive potential for the anode and auxiliary electrode, and means for adjustably connecting the anode to a point of less positive potential on the source than the point to which the auxiliary electrode is connected, and means for simultaneously controlling the said tuning elements to tune the said circuits to a common desired signal frequency and means for coupling the auxiliary electrode circuit to a. low frequency load circuit.

ROMYN VELDHUYZEN. 

